Process of manufacturing paper pulp



Patented a... so, 1931.

martial v STATES PATENT OFFICE HAMILTON 'D. WAGNON, OF IPALOUSE, WASHINGTON 7 rnocnss' or muracrunme PAPER 'IPULZP f No Drawing. I

The object of this invention is to effect economies in the process-as heretofore followed, said economies to be principally in the a composition of the digester liquor, in the time of required cooking, and in the use of the screenings after-thecooking process.

I accomplish-these objects by means of the. process as follows:

The material, preferably straw, is cut'into short lengths ready to be deposited in the digester, wherein-has previously been deposited the digesting liquid composed of fourparts of sal soda to one partof quick lime, to which is added one gallon of hydrocarbon oil for each ton of material to be treated,-the resulting liquid being of .a specific gravity test known as 2 Baum scale. Herein lies one of the economies sought to be accomplished,-

since the digesting liquid heretofore used has been of a specificgravity test of 14 Baum. 'I'othe digesting liquid I add one gallon of. hydrocarbon oil, such as kerosene. or the like,

' for each-ton of material to be cooked. The object of said oil is to lubricate the fibrous par-- ticles of the material, and thus aid in their separation from each other, such aid being observable both in the digester and in the rod mill subsequent to the digester ashereinafter,

explained.

4 The use ofsaid oil, and the introduction of the rod mill to be hereinafter explained,so aids in the separation of the fibrous particles as to greatly reduce the required time of cooking in the digester. Heretofore' the ma- .terial hasbeen cooked in the digester for a period of eight hours, but by my process I accomplish the necessary results of the cook .ing in approximately two hours. Therefore plished is eflected, the reducing of the time for cookingapproximately seventy-five percent. q

' {Due to the short period. of cookin in the digester, by my process the materia is but partially cooked that is 'incomparison to the present PIOCGISS Of much longer cooking, so thatwhile in'the present process the fibrous particles are completely separated in the di- 5 'gester, and are thus converted into pulp the second economy sought to be accom-' readyfor the paper machine, in my improved Application filed re mar 'is, 1929. Serial in. 341,277.

process the fibrous particles are not completely separated. Indeed the cooked ma- .terial of my process comes from the digester retaining the appearance of the raw material as it entered the digester, However all the cellulose in the material has been dissolved and removed by the cooking.

The cooked material is then deposited within'a rod mill, such a device being well known 7 to the art and therefore not described in .detail herein. Therein, by the mechanical process of grinding, thefibrous particles are thoroughly separated, and the cooked material reduced to pulp; The above mentioned oil having thoroughly lubricated the fibrous particles greatly facilitates the grinding process within said rod mill.

From the rod mill thepulp is deposited upon a screen, and the screenings, bywhich will be understood all the material that does not pass-through said screen, are again deposited -within the rod mill to-be further ground. Thus the third economy is accomplished, because all the material is eventually converted into usable pulp, while with the process heretofore used the screenings were more or less waste, being usable only for a very coarse and cheap grade of paper board.

' Having disclosed my process so that others may be enabled to follow and use the same,

desire to secure. by

In witness whereof 'I claim'the foregoing as my own I hereunto aflix my signature at Portland, county of Multnomah, State .of Oregon, this 14th day of Feb., 1929.

f HAMILTON n. WAGNON..- 

